产碱杆菌属内α-N-乙酰半乳糖胺酶对氨基酸-O-聚糖的作用：与肺炎双球菌来源的酶的比较。
Action of endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. on amino acid-O-glycans: comparison with the enzyme from Diplococcus pneumoniae.
作者信息
Fan J Q, Yamamoto K, Matsumoto Y, Hirabayashi Y, Kumagai H, Tochikura T
机构信息
Department of Food Science and Technology, Kyoto University, Japan.
出版信息
Biochem Biophys Res Commun. 1990 Jun 15;169(2):751-7. doi: 10.1016/0006-291x(90)90395-4.
Endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. released the disaccharide, Gal beta 1----3GalNAc, from both dansylated serine-GalNAc-Gal and threonine-GalNAc-Gal, and showed higher activity on the former than the latter. The Km values were 0.17 mM and 1.43 mM with DNS-Ser-GalNAc-Gal and DNS-Thr-GalNAc-Gal, respectively. The optimum pHs were found to be 4.5-7.5 and 4.5-6.0 on DNS-Ser-GalNAc-Gal and DNS-Thr-GalNAc-Gal, respectively. On the contrary, the enzyme from Diplococcus pneumoniae had low activity to release the disaccharide from the amino acid-O-glycans. The possibility that the same O-glycoside but linked to different aglycon amino acids may play a different biological role in glycoproteins is discussed.
来自产碱菌属的内切α-N-乙酰半乳糖胺酶从丹磺酰化丝氨酸-GalNAc-Gal和苏氨酸-GalNAc-Gal中释放出二糖Galβ1----3GalNAc，并且对前者的活性高于后者。以DNS-Ser-GalNAc-Gal和DNS-Thr-GalNAc-Gal为底物时，Km值分别为0.17 mM和1.43 mM。在DNS-Ser-GalNAc-Gal和DNS-Thr-GalNAc-Gal上，最适pH分别为4.5 - 7.5和4.5 - 6.0。相反，肺炎双球菌的酶从氨基酸O-聚糖中释放二糖的活性较低。本文讨论了相同的O-糖苷与不同的糖苷配基氨基酸相连可能在糖蛋白中发挥不同生物学作用的可能性。
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